Induction heating apparatus



ATTORNfY Jan. 19, 1954 F. LAVER INDUCTION HEATING APPARATUS Filed March 9, 1951 7/ a a a n f WV A 4 6 0 L F 4 6 J M r v, F A a o 3 ,7 I f Q 6 a J /u 0 4m 4 8 II I 8 .3 mm a w H 1 1 I a 6 4 M u Ptu M.\ 2 a B a Patented Jan. 19, 1954 NITED STATES PATENT OFFICE INDUCTION HEATING APPARATUS Frank Laver, Oak Park, Ill., assi'gnor to Wcstern Electric Company, Incorporated, New York, .N. Y., a corporation of New York Application'March 9, 1951,,Seria1No. 214,761

(Cl. -2'l:9:47:)

ous designs for various purposes to be used at different times and which may individually be connected to and energized from a common high frequency current generating unit.

It is an object of the present invention to provide a simplified arrangement for cooling a plurality of induction heating coils in a high frequency current induction heating apparatus and for selectively electrically connecting the coils to a source of high frequency current.

In accordance with one embodiment of the invention there is provided a high frequency current generator connected through a pair of tubular leads to a pair of h llow'movable contact members which are movable into engagement with pairs of hollow contacts connected through tubular leads to a plurality of tubular induction heating coils for electrically connecting the coils individually to the high frequency current generator. Lengths of rubber tubing connect one hollow contact of each pair of contacts with the other of another pair of contacts and serve with the tubular leads to physically connect all coils and contacts in series and establish communication among them for thecirculation of a coolant therethrough.

Other objects and advantages of the invention will become apparent by reference to the following detailed description thereof and the accompanying drawing illustrating a preferred embodirnent of the invention, in which Fig. 1 is a diagrammatic view of the high frequency induction heating apparatus;

Fig. 2 is a vertical, sectional, elevational view of the switch mechanism of the apparatus; and

Fig. 3 is a vertical, cross-sectional view of the switch taken on the line ..33 of Fig. 2.

Referring to Fig. 1 of the drawing, there is shown three induction heating coils [0, H and 112, each individually connectible to a suitable source of high frequency current such as electronic high frequency generating unit indicated at M. Individually designed for special purposes, the induction heating coils ll), H and I2 have shapes difiering from :each other for receiving and heating different parts. .Each :of "the heating coils ill, H and I2 comprises a tubular metal coil having tubular leads l6 extending 'irom'the coil to one end of a pair of hollow stationary contact members [8 and 19.

A pair of movable hollow contacts 20 and 2| have connected thereto at one end, one end of a pair of flexible metal tubular leads 24 which at their other ends are connected to the high frequency current generator Ml. By selectively engaging the contacts Zli and 2| with any pair of the stationary contacts l8 and 19 any one of the induction heating coils Ill, Ii and I2 may be connected to the high frequency current generator M to energize the coil. Lengths of flexible tubing 26 of insulating material, such as rubber, connect one of each pair of contacts with the other of another pair of contacts, the contacts i8, I9, 26 and 2i, the lengths of flexible rubber tubing it, the tubular metal leads 24,

and the coils Ill, ll and I2 being arranged as shown in Fig. 1 so that all of the contacts and the coils communicate with each other in series. Water or other coolant supplied through lines 28 to the tubular leads Ed is circulated through all of the stationary and movable contacts and the induction heating coils and [2.

The stationary and the movable contacts l8, !9, 2t and 2!, the lengths of flexible rubber hose 26,-and a portion of the flexible tubular leads 24 connected thereto are enclosed within a switch The switch box bottom wall 33, and a top wall or cover 34 hinged at 35 and provided with a latch or locking means 36 for retaining the cover in closed position. A shelf 38-of insulation within the switch box supports the stationary contact elements I8 and [9 in spaced relation to each other and the Walls of the switch box to provide space and clearance for the tubular connections thereto. The hollow stationary contacts are provided with V-shaped .upper walls forming grooves for receiving the movable contacts 28 and 2| having V-shaped lower surfaces conforming to the V-shaped grooves in the stationary contacts.

The movable contacts are attached to a plate for locating the movable contacts 20 and 2&1

properly on the stationary contacts l8 and I9 and preventing lateral displacement thereof. Pairs of leaf springs 44-44 mounted on the cover 34 above each pair of stationary contacts engage the plate 40 when the cover is closed and serves to press the movable contacts 20 and 2| into firm engagement with the stationary contacts l8 and I9.

The flexible leads [6 from the heating coils III, II and I2 to the stationary contacts I8 and I9 pass through apertures in the bottom and side wall of the switch box as shown in Fig. 3 and are secured thereto by suitable connections 46. Leads 24 from the movable contacts 20 and 2| to the high frequency current generator pass through a longitudinal slot 48 in the bottom 33 of the switch box, clearance being provided thereby for movement of the pair of movable contacts 20 and 2| from one position to another for engagement with the several pairs of stationary contacts l8 and IS.

The primary current to the high frequency generating unit !4 is supplied with a power line 5!) under control of a switch 5!. In order to insure that the high frequency current to the able into closed position when the relay 52 is energized to complete the power circuit to the high frequency generator M. A normally open microswitch 55 is locatedwithin the switch box and is actuated to its closed position when the cover 3c is closed, and serves to complete the circuit to and energize the relay 52 to close the power circuit to the high frequency generator l4, and upon the opening of the cover the switch 55 serves to deenergize the relay and disconnect the high frequency generator M from the power.

With the coils ii), I l and i2 cooled by the continuous circulation of coolant therethrough, it is a relatively simple matter to operate the switch and connect any one of the coils to the high frequency current generator. For example, if it is desired to connect the induction heating coil H to the high frequency current unit, after switch 5! has been opened to disconnect the power from the high frequency current generator, the cover of the switch box is opened, and the movable contacts 2d and 2! are moved into engagement with the stationary contacts i8 and i9 associated with the induction heating coil H. The cover is then closed and locked in closed position with the locking device 35 thereby closing switch 55, and the switch ti is then closed which effects the closing or contacts 53 to supply primary power to the high frequency generator, which in turn will then supply high frequency current to the heating coil ii. Thus with this high frequency induction heating apparatus with its simplified switch and coil cooling arrangement, any one of the induction heating coils may be electrically connected to the high frequency generator with- It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of this invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. A high frequency heating apparatus comprising a plurality of hollow heating coils having hollow leads, a pair of hollow contact members connected to the leads of each of said coils, a high frequency current generator having a plurality of flexible hollow leads connected thereto, a plurality of movable hollow contacts connected to said flexible hollow leads, said movable contacts being selectively engageable with the pairs of contacts associated with said coils to electrically connect said coils to said high frequency current generator, and flexible hollow members of electrical insulating material interconnecting the hollow contacts and cooperating with the flexible hollow leads and coils to form a single continuous conduit for circulating a coolant through all of said coils and said contacts and for maintaining said coils in insulated relation to each other.

2. An induction heating apparatus comprising a plurality of hollow heating coils having hollow leads, a pair of hollow contact members connected to the leads of each of said coils, a high frequency current generator having a pair of flexible hollow leads connected thereto, a pair of movable hollow contacts on said leads, said movable contacts being selectively engageable with the pairs of contacts associated with said coils to electrically connect said coils to said high frequency current generator, and flexible conduits of electrical insulation interconnecting the hollow contacts and cooperating with the flexible hollow leads and coils to form a single continuous conduit for circulating a coolant through all of said coils and said contacts and for maintaining said coils in insulated relation one to another.

3. In an induction heating apparatus, the combination of a plurality of tubular metal heating coils having tubular leads extending therefrom, a pair of hollow first contact members connected to the leads from each of said coils, a pair of hollow second contact members having tubular leads connectible to a source of high frequency current, said second contact members being movable into engagement with the first contact members to selectively connect said coils to said source of current, and a plurality of hollow electrical insulating members connected to said contact members, each of said hollow insulating members establishing communication between two of said contact members and cooperating with said tubular leads to form a conduit establishing communication in series with all of said coils for the circulation of a coolant therethrough.

4. In an induction heating apparatus, the combination of a plurality of tubular metal heating coils having tubular leads extending therefrom, a pair of hollow first contact members connected to the leads from each of said coils, a plurality ,of hollow second contact members having tubular leads connectible to a source of high frequency current, said second contact members being movable into engagement with the first contact members to selectively connect said coils to said source of current, a plurality of hollow insulating members connected to said contact members, each of said hollow insulating members establishing communication between two of said contact members and cooperating with said tubular leads to form a conduit establishing communication in series with all of said coils, and means for directing coolant into said conduit.

5. An induction heating apparatus comprising a plurality of tubular heating coils having tubular leads extending therefrom, a pair of hollow first contact members connected to the leads from each of said coils, a first means supporting said first contact members in predetermined fixed relation to each other, a plurality of second hollow contact members having tubular leads connectible to a source of high frequency current, a second means supporting said second contact members in predetermined fixed relation to each other, one of said supporting means being movable relative to the other to permit the engagement of said first contact members with said second contact members to selectively connect said .coils to said source of current, and a plurality of insulating conduits connectedto said hollow contacts and cooperating with said tubular leads to form a continuous conduit establishing communication in series with all of said coils for the passage of coolant therethrough and for maintaining said coils in'insulated relation one to another.

6. An induction heating apparatus comprising a source of high frequency currentya plurality of tubular heating coils having tubular leads extending therefrom, a pair of hollow first contact members connected to the leads from each of said coils, a first means supporting said first contact members in predetermined fixed relation to'each other, a pair of second hollow contact members having tubular leads connected to said source of high frequency current, a second means supporting said second contact members in predetermined fixed relation to each other, one of said supporting means being movable relative to the other to permit the engagement of said first contact members with said second contact members to selectively connect said coils to said source of current. and a plurality of hollow insulating members connected to said hollow contacts, each of said insulating members establishing communication between two of said contact members and cooperating with said tubular leads to form a continuous conduit establishing communication in series with all of said coils for the passage of coolant therethrough.

7. An induction heating apparatus comprising a plurality of hollow heating coils each having a. pair of hollow leads extending therefrom, a pair of hollow stationary contact members connected to the pair of leads from each of said coils, a plurality of movable hollow contact members having hollow leads connectible to a source of high frequency current, said movable contact members being movable into engagement with the stationary contact members to selectively connect said coils to said source of current, a plurality of hollow insulating members connected to said contact members, each of said insulating members establishing communication between the two of said contact members and in cooperation with said hollow leads forming a continuous conduit means establishing communication in series with all of said coils for the passage of a coolant therethrough, and means for directing coolant into said conduit means.

8. An induction heating apparatus comprising a source of high frequency current, a plurality of hollow heating coils each having arpair of hollow leads extending therefrom, a pair of hollow stationary contact members connected to the pair of leads from each of said coils, a plurality of movable hollow contact members having hollow leads connectible to a source of high frequency-current, said movable contact members being movable into engagement with the stationary contact members to selectively connect said coils to said source of current, a plurality of hollow insulating members connected to-said contact members, and cooperating with said hollow leads and coils to form a single continuous conduit means establishing communication in series with all of said coils for the passage of a coolant therethrough and for maintaining said coils in insulated relation one to another, and means for directing coolant into said conduit means.

FRANK LAVER.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,635,581 Meadowcroft July 12, 1927 2,321,189 Dravneek June 8, 1943 4 2,496,950 Marcus et a1 Feb. '7, 1950 2,517,425 Grumel Aug. 1, 1950 FOREIGN PATENTS Number Country Date 670,634 France Dec. 2, 1929 

